<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
      * {
        padding: 0;
        margin: 0;
      }
      body {
        width: 100%;
        height: 100vh;
        background: linear-gradient(
          130deg,
          red,
          green,
          #433351,
          #a10c31,
          #430fbb,
          #129ac4
        );
        background-size: 400%;
        background-position: 0% 50%;
        animation: move 5s ease infinite alternate;
      }
      @keyframes move {
        0% {
          background-position: 0% 50%;
        }
        100% {
          background-position: 100% 50%;
        }
      }
    </style>
  </head>
  <body></body>
</html>
